package demo3;

public class Computer {
    public void powerOn(){
        System.out.println("打开电脑");
    }
    public void powerOff(){
        System.out.println("关闭电脑");
    }

    public void usbDevice(USB usb){
        usb.openDevice();
        if(usb instanceof KeyBoard){
            KeyBoard keyboard = (KeyBoard)usb;
            keyboard.dazi();
        }else if(usb instanceof Mouse){
            Mouse mouse = (Mouse)usb;
            mouse.click();
        }
        usb.closeDevice();
    }

}
